1. Field of the Invention:
This invention relates to a supported catalytic component for .alpha.-olefin polymerization which has a greater titanium content therein than the conventional Ziegler type supported catalytic component, highly uniform particle diameter, a high degree of polymerizing activity and high productivity for a stereospecific polymer. The invention also relates to a method for homo- or co-polymerization of an .alpha.-olefin in which polymerization is carried out in the presence of a catalyst system which consists of the above stated supported catalytic component and an organo-aluminum compound. More particularly stated, the invention elates to a Ziegler type supported catalytic component which is obtained with an inert hydrocarbon compound employed as solvent and by allowing therein a carbon tetrahalide and an organo-magnesium compound to react with each other in the presence of an organic acid ester to obtain a solid matter; by treating the solid matter with an organic compound of phenol (hereinafter will be called the phenol compound); and then by treating the solid product with a halogen-containing titanium compound. The invention also relates, as mentioned in the foregoing, to a method for homo- or co-polymerization of an .alpha.-olefin which is carried out in the presence of a catalyst system consisting of the above stated supported catalytic component and an organo-aluminum compound.
2. Description of the Prior Art:
The conventional catalytic components that are suitable for use in manufacturing a stereospecific .alpha.-olefin polymers include a catalytic component obtained by activating through a pulverizing process or the like an eutectic mixture consisting of aluminum chloride and titanium trichloride which is obtained by reducing titanium tetrachloride with metal aluminum in the presence of aluminum chloride; and a catalytic component which is obtained by reducing titanium tetrachloride with an organo-aluminum compound to obtain titanium trichloride and by treating the titanium trichloride with an organic ether compound and titanium tetrachloride to activate. In carrying out polymerization of an .alpha.-olefin, the catalytic component is used ordinarily by combining it with an organo-aluminum compound into a catalyst system. An .alpha.-olefin polymer obtained by carrying out polymerization in the presence of this catalyst system contains therein several hundred ppm of the residue of the catalyst. Then, a transition metal such as titanium and halogen remaining within the polymer come to accelerate deterioration of the polymer. Therefore, they must be removed as much as possible from the polymer. Hence, a polymer produced in this manner has been washed with an alcohol to remove the residue of the catalyst in the manufacture of the polymer.
In efforts to lower the cost of the manufacture of an .alpha.-olefin polymer, there have recently been proposed many kinds of catalytic components that have polymerizing activity in a sufficient degree to permit an .alpha.-olefin polymer manufacturing operation to exclude a deashing process that have been necessary for washing and removing a transition metal, such as titanium, from a polymer product. What is aimed at by these catalytic components in such that the transition metal content such as titanium remaining in a polymer produced can be reduced to several ppm or less than that by making the quantity of the polymer produced to one hundred thousand to several hundred thousand parts by weight per unit part by weight of the transition metal such as titanium. Then, this would obviates the necessity of having the deashing process and would contribute to reduction in the cost of manufacture of an .alpha.-olefin polymer. Most of them are supported catalytic components of the so-called Ziegler type and are prepared in the following manner:
A magnesium chloride or a magnesium chloride which has undergone some surface treatment is used as support to have titanium tetrachloride supported on the surface thereof. However, in the case of a method where a support which in mainly composed of magnesium chloride is processed in titanium tetrachloride to have titanium supported on the support, it is difficult to enable the support to support titanium if the magnesium chloride is used as it is and a catalytic component thus obtained does not have a sufficient effect on the polymerization of an .alpha.-olefin. To solve this problem, it has been considered necessary to have the magnesium chloride surface treated by some suitable method.
Examples of methods for obtaining catalytic components of the above stated type include: A method disclosed by a Japanese patent application laid-open No. 48-16986 in which a complex consisting of titanium tetrachloride and an organic acid ester is mixed with anhydrous magnesium chloride and is pulverized together; and another method disclosed by a Japanese patent application laid-open No. 53-108088 in which anhydrous magnesium chloride, an organic acid ester and silicone oil are pulverized together; and a matter obtained by this pulverization process is treated by an active hydrogen compound, an organic metal compound and titanium tetrachloride.
However, with an .alpha.-olefin polymerized by using a catalytic component prepared in accordance with such methods, the productivity for a stereospecific polymer is not satisfactory. Meanwhile, depending upon the polymerizing conditions employed, several hundred of thousand parts by weight of a polymer is sometimes obtainable per unit part by weight of titanium which is a transition metal. However, since the catalytic component contains only 1 to 3% by weight of titanium, if this is calculated in terms of an amount of the polymer produced per unit part by weight of the whole catalytic component, the amount of the polymer produced is only several thousand part by weight. In other words, although the amount of titanium contained in the polymer is not much, there are contained large amounts of magnesium and chlorine. Therefore, it is still necessary to remove halogen while removal of the transition metal such as titanium from the polymer may be no longer necessary. Besides, the amount of magnesium contained in the polymer is also not negligible. This problem is attributable to the fact that the quantity of the transition metal such as titanium supported on the support is small and is normally 1 to 30% by weight of the support. Such being the situation, even where polymerizing activity per unit weight of titanium is high, when this is calculated in terms of the polymerizing activity per unit weight of the catalytic component, the degree of polymerizing activity of the catalytic component is still not high enough to permit omission of the deashing process.
To solve this problem, there has been also proposed a method by a Japanese patent application laid-open No. 49-86482 in which the concentration of halogen is lowered by a support which is used as co-support. However, with a catalytic component prepared in accordance with this method, the weight of a polymer produced per unit weight of the catalytic component is lessened as much as the quantity in which this co-support is used. Therefore, this method fails to solve the problem.
As for a proposition based on a completely different viewpoint, there has been proposed a Ziegler type catalytic component in which a matter which is not magnesium chloride and does not contain halogen at all is used as support. However, this catalytic component is inferior in polymerizing activity and productivity for a stereospecific polymer. Thus, there has not been proposed any catalytic component that is considered useful for industrial applications.
Meanwhile, the inventors of the present invention came to form a conception that the above stated shortcomings of the prior art could be eliminated by increasing the quantity of titanium that can be supported on a support and by giving some treatment that renders the whole of the supported titanium effectively operative. They have strenuously conducted studies to eventually discover that an .alpha.-olefin polymerizing catalytic component which has a great quantity of titanium supported on a support to have a high rate of polymer formation per unit weight of titanium and also per unit of the catalytic component and which has a high degree of productivity for a stereospecific polymer can be obtained by allowing an organo-magnesium compound and carbon tetrahalide to react with each other in an inert organic solvent in the presence of an organic acid ester to obtain a solid product of reaction; they by treating this solid reaction product with a phenol compound; and further by treating it with a halogen containing titanium compound. The present invention has resulted from this discovery.